I actually have heard great things about AZCOM myself. But be aware, that EVERY school has is negatives.
I think I see what you are saying, you are saying that if you go to AZCOM and then find out after two years that you really hate OMM or osteopathy, then what would you do? The answer to that is real simple, stay at AZCOM and finish your thrid and fourth years? why??
Because OMM is one of those things that you are not obligated to do once you become a practicing DO, yeah you may need to review the basics of OMM to pass your boards, but if you are a DO, and you dislike OMM, and you never want to use it ever again, then it can be done!!!
That is the biggest advantage of the DO degree, you have to learn the basics of OMM to pass your boards, but after that, you can take OMM as seriously as you want, and you still get to learn all of the medicine that the MD's learn.
But lets be straight, there are some disadvantages of DO too, one thing is, right now, you can't practice overseas with a DO degree. Second, the AOA doesn't offer as many osteopathic residency programs as there are DO gradutaes. This really is not much of a problem though because as long as you do an AOA internship, you can do and MD residency, many hospitals don't care what your degree is.
So if you really like AZCOM and you think that its your home, then go for it, don't let the DO thing stop you, the only thing that you will be limited by is the fact that you can't practice overseas.